Due to the rapid development of information and communication technologies, many activities in our daily life have been merged online and they become more flexible and more effective. A huge growth of online users number has activated virtual word concepts and created a new business phenomenon which is virtual currency to facilitate the financial activities such as buying, selling and trading. Virtual currency represent valuable and intangible objects which are used electronically in different applications and networks such as online social networks, online social games, virtual worlds and peer to peer networks. The use of virtual currency has become widespread in many different systems in recent years. This paper investigates and analyses ...